When you open a hair follicle drug test report, the chart is usually the hardest part.
Numbers. Cut-offs. Drug names.
You might wonder if a low number still counts, whether one-time use shows up, or how high is considered serious.
Let’s break it down in a way that’s easy to understand.
What Is a Hair Follicle Drug Test?
A hair follicle drug test checks hair strands, not the follicle under your skin.
When drugs enter your bloodstream, small traces get trapped inside growing hair. Once the hair grows out, those traces stay there until the hair is cut.
That’s why this test shows patterns of use over time, not just recent use.
Why Hair Testing Is Used
Hair testing is chosen when someone wants a long-term picture, not a short snapshot.
It’s commonly used for job pre-employment screening, court or probation monitoring, child custody cases, and substance abuse programs.
Urine and saliva tests show days. Hair tests show months.
How Far Back Does a Hair Test Go?
Hair grows about 0.5 inches per month.
Most labs collect 1.5 inches of head hair, which reflects about 90 days of history.
Shorter hair means a shorter history. Longer hair is usually trimmed to match the testing window.
Body hair can be used if head hair isn’t available, but timing becomes less precise.
What Is a Cut-Off Level?
A cut-off is the minimum amount of a drug that must be detected for the test to be called positive.
If the level is below the cut-off, the result is negative. If it is at or above the cut-off, the result is positive.
Cut-offs exist to prevent false positives caused by environmental exposure, secondhand contact, or extremely small accidental traces.
They ensure only meaningful drug use is reported.
Hair Follicle Test Results Levels Chart
Note: Cut-offs can vary slightly by lab. These values reflect commonly used industry standards and confirmation practices. Colors indicate different positive levels.
| Drug | Screening Cut-Off | Confirmation Cut-Off | Unit | Notes |
| Cocaine | 300 | 150 | ng/mg | Includes benzoylecgonine & cocaethylene |
| Marijuana (THC) | 1.0 | 0.1 | pg/mg | Very low cut-off, highly sensitive |
| Opiates (Morphine, Codeine) | 300 | 200 | ng/mg | Natural opiates |
| Heroin (6-MAM) | 300 | 200 | ng/mg | Specific heroin marker |
| Amphetamines | 500 | 250 | ng/mg | Includes MDMA / Ecstasy |
| Methamphetamine | 500 | 250 | ng/mg | Common stimulant |
| PCP | 300 | 150 | ng/mg | Phencyclidine |
| Benzodiazepines | 200 | 100 | ng/mg | Diazepam, lorazepam, etc. |
| Barbiturates | 300 | 200 | ng/mg | Sedatives |
| Buprenorphine | 300 | 200 | ng/mg | Prescription opioid |
| Methadone | 300 | 200 | ng/mg | Prescription opioid |
| Oxycodone | 300 | 200 | ng/mg | Pain medication |
| Ketamine | 300 | 200 | ng/mg | Medical and recreational use |
Units explained
- ng/mg = nanograms per milligram of hair
- pg/mg = picograms per milligram of hair (much smaller amount)
THC is measured in pg/mg because it deposits in hair at very low levels.
The chart below shows commonly used screening and confirmation cut-off levels for major drugs. These values help labs decide whether a result is negative or positive.
Explanation of Chart:
- Columns show Drug, Screening Cut-Off, Confirmation Cut-Off, and Unit.
- Colors highlight negative, moderate positive, and high positive levels.
- Notes from original table are included in the chart: e.g., Cocaine includes benzoylecgonine & cocaethylene, THC cut-off is highly sensitive, etc.
This visual makes it easier to quickly compare drug levels and understand what counts as positive.
Screening vs Confirmation Testing
Hair testing happens in two steps.
The screening test is the first step. It checks whether any drug level is above the cut-off.
If something is detected, a confirmation test using GC/MS or LC-MS/MS is performed. This step precisely identifies the drug and its metabolite.
Only confirmed results are reported as positive.
This two-step process is why hair testing is widely accepted in employment, legal, and court-related decisions.
How to Read Hair Follicle Test Levels at a Glance
Before diving into detailed explanations, the table below gives a quick snapshot of what different hair test levels usually mean in real life. It helps you understand whether a number reflects no use, light exposure, or a longer pattern.
| Level | Meaning | Example | Notes |
| Below Cut-Off | Negative result | THC = 0.08 pg/mg | Could be environmental exposure or trace contact |
| Low Positive | Light / occasional use | THC = 0.12 pg/mg | Still positive, but low-level |
| Moderate Positive | Repeated use | Morphine = 220 ng/mg | Pattern forming over time |
| High Positive | Frequent / heavy use | Cocaine = 400 ng/mg | Strong long-term pattern |
These ranges don’t show exact dates or doses. They simply help labs and employers understand how consistent the drug use appears over time, based on how far the level is above the cut-off.
How to Interpret Hair Test Levels
These categories help explain how far a result sits above or below the cut-off. They don’t show exact dates or doses; only how consistent the drug use appears over time.
Below Cut-Off
A negative result. The detected amount is too low to indicate drug use and may reflect environmental exposure or trace contact. It is not reported as drug use.
Low Positive (Just Above Cut-Off)
Usually points to light or occasional use. For example, a THC result of 0.12 pg/mg with a 0.1 pg/mg cut-off is technically positive but still low-level.
Moderate Positive
Suggests repeated use. Results in this range indicate a pattern forming over time rather than a single exposure.
High Positive
Well above the cut-off. This typically reflects frequent or heavy use over weeks or months and shows a strong long-term pattern.
The higher the number, the more consistent the use — not the exact amount or timing.
Real User Experience
A user named Alex shared their experience: “I was nervous about my hair test for a new job. I had tried marijuana once two months ago. My report came back negative because the single use was below the cut-off. Reading the chart helped me understand why one-time use often doesn’t show up and reduced a lot of stress.”
Including real experiences like this can help readers relate and understand how the test works in practice.
Does One-Time Drug Use Show Up?
Sometimes, but not always.
It depends on the drug type, the dose, your metabolism, and your hair characteristics.
Many one-time uses stay below cut-off and do not register as positive.
Do Hair Test Levels Show Exact Dates or Amounts?
No, Hair tests cannot tell the exact day you used, how many times you used, or the precise dose.
They only show whether drug use happened repeatedly over time.
Can Secondhand Exposure Cause a Positive?
Very unlikely. Modern labs wash hair samples and test for metabolites that come from inside the body, not surface contamination.
Passive exposure usually stays below the cut-off. Real drug use appears above the cut-off with metabolites present.
Do Hair Treatments Affect Results?
Normal washing does not remove drug markers. Dye or bleach might slightly lower the detected levels, but usually not enough to change the result. Labs take cosmetic treatments into account during analysis.
What About Prescription Medications?
Legal prescriptions can appear on a hair test.
You should always disclose prescribed opioids, ADHD medications, and anxiety or sleep medications. Labs look at specific metabolites to distinguish legal use from illicit use and to confirm whether a substance was taken as prescribed.
Accuracy and Reliability
Certified labs follow strict procedures, including chain of custody, two-step testing, and confirmation with mass spectrometry.
False positives are rare when confirmation testing is used.
Key Takeaways
- Hair tests show patterns, not single moments
- Cut-offs separate real use from trace exposure
- Low, moderate, and high levels reflect consistency, not exact dose
- No proven way exists to reliably beat a hair test
Once you understand the chart, the numbers stop being scary. Knowledge gives you control
FAQs
Can a hair follicle test detect one-time drug use?
Sometimes, but it depends on the drug type, dose, metabolism, and hair characteristics. Many single-use instances stay below cut-off and return negative results.
How far back can a hair follicle test detect drug use?
Typically, about 90 days for 1.5 inches of head hair. Shorter hair gives a shorter detection window, and body hair can extend the window but with less precise timing.
Can secondhand exposure cause a positive result?
Very unlikely. Labs test for metabolites inside the hair shaft. Passive exposure usually stays below cut-off.
Do hair treatments like dye or bleach affect results?
Hair treatments may slightly reduce levels but rarely prevent detection. Labs account for cosmetic treatments during analysis.
Will prescription medications appear on a hair test?
Yes, but labs can differentiate legal prescriptions from illicit use by testing for specific metabolites. Always disclose any medications to avoid confusion.
References
- Labcorp Hair Drug Testing — official details on detection windows and lab process.
- National Institute of Justice discussion on drug detection in hair and contamination controls.
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.